Why the last interglacial?

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  • Quaternary International, Vol. 10-12, pp. 5-6, 1991. 1040-6182/91 $0.00 + .50 Printed in Great Britain. All rights reserved. 1992 lNQUA/Pergamon Press Ltd



    When the International Council of Scientific Unions (ICSU) announced the International Geosphere- Biosphere Program (IGBP); A Study of Global Change a few years ago, Quaternarists, among others, began exploring ways on how they could contribute to the Program's goals. The focus of the IGBP is to document and describe the interactive physical, chemical and biological processes that regulate the total Earth system, the unique environment that it provides for life, the changes that are occurring in the system, and the manner in which those are influenced by human actions. To accomplish this noble but extremely ambi- tious endeavor, documentation and description of past global changes is paramount in understanding the present, and for predicting the future. The Planning Group recognized this early on, with the eventual formation of a Scientific Steering Committee on Gobal Changes of the Past (later, PAGES), ensuring a place for Quaternary scientists. In order to keep the program broad and to accommodate as many as possible, the Steering Committee agreed on two major streams of research objectives. These include Stream I, the objec- tive of which is to reconstruct the detailed history of climatic and environmental change for the entire globe for the period since 2000 B.P., with temporal resolution that is at least decadal, and ideally annual or seasonal; and Stream II, the objective of which is to reconstruct a history of environmental change through a full glacial cycle, in order to improve our understanding of the natural processes that invoke global climatic changes.

    It is with the second stream in mind that a group of Canadian and American Quaternary scientists develo- ped a project to document the climate and environment of the last interglacial in Arctic and Subarctic North America (CELIA). It was recognized that a better knowledge of Quaternary climates at high northern latitudes is essential to predict natural and anthropolo- gical global climate changes. The Arctic plays a crucial role in the global climate system. It includes some of the most dynamic boundary conditions of the planetary ocean-atmospheric system: the extent and duration of sea ice, the geography (area and elevation) of sea ice, the geography (area and elevation) of continental ice sheets, the position of tree line, the distribution and duration of seasonal snow cover and permafrost, the boundary between polar and subpolar ocean surface waters. How these parameters control energy ex- changes and rates of climate change, and whether anticipated changes in these parameters can be pre-

    dicted, is one of the major scientific challenges of the coming decade. The study of how these boundary conditions have differed in the recent geologic past, and reconstructing the concomitant climate change as presented in the proxy records, is the role of Quater- nary scientists. Paleoclimatic data derived for specific intervals of the Late Quaternary define the rates of mechanisms of climate change, and provide one of the only means of validating general circulation models.

    So why the last interglacial? We can anticipate and prepare for the changes of the near future by gaining precise knowledge on past intervals of warmer climate. In order to achieve this, a 'control situation' free of human influences is required. A reconstruction of the paleoclimate and paleoenvironment during the last interglacial (Isotope Stage 5) particularly Isotope Stage 5e, the youngest period with climatic conditions war- mer than today, is a 'natural'. Therefore, the CELIA project was designed to generate and synthesize data on Isotope Stage 5 from high latitude terrestrial and near-shore marine environments in North America and Greenland, test hypotheses generated by general circu- lation models and other 'warm earth' or interglacial simulations, to provide background information into future environments resulting from anthropogenic global-changes, and directly contribute to the objec- tives of Stream II of IGBP's core project on Global Changes of the Past (PAGES). Project CELIA will accomplish this by field and laboratory research selected in high latitude sites where a variety of paleoecological and proxy climatic methods will be employed. Quantitative information should be impor- tant in supplementing and enriching the qualitative data sets. As a result of these qualitative and multi- disciplinary inputs, CELIA will provide a broader and more complete view of the paleoenvironment of the last interglacial than has heretofore been possible.

    It became apparent to members of CELIA, that although Project CELIA is focused on northern North America, in reality it is a part of a burgeoning world- wide effort to achieve a better understanding of past global change, particularly a change to warmer condi- tions. Thus it is important for CELIA participants to establish contact with those working on interglacial problems elsewhere in high latitudes and to establish working relationships in order to exchange, coordinate and contribute knowledge and information. Similarly, it is desirable that other groups be aware of the approach and techniques to be used by CELIA

  • 6 Preface

    researchers. To achieve this, a workshop was proposed to initiate contact with key scientists and to focus on such items as the current state of knowledge, scientific problem areas, needs for future research, and coordi- nation and interpretation strategies. Knowing that NATO (North Atlantic Treaty Organization) was interested in IGBP: A Study of Global Change, a formal application for an Advance Research Workshop on the Climates and Environment of the Last Intergla- cial in the Arctic and Subarctic was made to the Scientific Affairs Division. Happily, the application was approved and the Advanced Research Workshop was held in Hanstholm, Denmark, October 19-22, 1990.

    A glance at the paper titles and authors in the Contents of this volume will attest to the success of the Workshop. Last interglacial environments are discus- sed for key areas circling the Arctic and Subarctic, including both the terrestrial and ocean records. In addition, papers on general circulation models and climatic forcing applicable to the high latitudes are presented, as well as ideas on the handling of proxy data. Two discussion group reports, where all partici- pants were involved with one or the other (or both), deal with the important topics of marine and terrestrial evidence, and the inter-relationship between the land, atmosphere and oceans for the last interglacial. Not only did good science come out of this Workshop but a feeling of camraderie between northern workers, enough in fact, for the group to ensure the continuation of this initiative by the formation of a working group on

    the Last Interglacial in the Arctic and Subarctic (LIGA). L IGA will foster the exchange of field-based paleoclimate data and increase communication be- tween field researchers and the modeling community by providing a global-scale data base and by serving as an interface between field-based Quaternary scientists and ongoing regional programs such as CELIA, addressing the field record of the last interglacial, and the climate modeling community.

    The Director, Organizing Committee and Partici- pants are indebted to the Scientific Affairs Division of NATO for recognizing the importance of our topic and sponsoring the Advance Research Workshop. We sincerely hope that we have more than fulfilled our obligation to NATO by providing what we think is an outstanding volume that will be useful to many.

    Nat Rutter, Director NATO Advanced Research Workshop,

    Edmonton, Alberta, Canada

    J.V. Matthews, Jr Ottawa, Ontario, Canada

    C.E. Schweger Edmonton,

    Alberta, Canada